The present invention relates to a process for the sterilization of pumps for liquid or pasty pharmaceuticals, cosmetics, foodstuffs or similar, preferably for pumps in which the piston is driven to slide longitudinally and in general vertically within a cylinder and to rotate around its own axis, where the piston contains a recess that reaches as far as the circular cylinder wall and the working face of the piston and communicates with a suction connection in the cylinder wall during a suction stroke and with a pressure connection in the cylinder wall during a pressure stroke and where, further, a closable drainage aperture is preferably provided in the bottom end of the cylinder.
Pumps of this kind, which are mainly used in installations for decanting pasty or liquid pharmaceutical or cosmetical products, have hitherto been sterilized in a dismantled state and under heat and pressure in an autoclave. It is also known for the pump cylinder to be left incorporated in the pump device, but laying the piston bare by withdrawing it through the upper end of the cylinder, and then treating both the piston and the cylinder with a sterilization medium. In the latter case the cylinder must be extended upwards with an enlarged bore and over a distance sufficiently long for it to surround the piston after it has been laid bare. Manufacturing costs are thus increased. In both cases, however, sterilization is associated with additional and costly work. In particular, there is the danger that the sterilized pump will become desterilized during its subsequent assembly.